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## The quadrillionth bit of Pi is '0'Between September 5, 1998 and September 11, 2000, one thousand seven hundred and thirty-four computers from fifty-six different countries set a new record for calculating specific bits of Pi. The previous record of this type was the calculation of the forty trillionth bit between April 1998 and February 1999, also by PiHex. This will be the final computation performed by PiHex. The calculation took a total of about 1.2 million cpu hours, and was done using 'idle' time slices (cpu time which no other program is using) on systems running windows 95, 98, NT, 2000, and Linux. The 'average' computer participating was a 450MHz Pentium II. The answer, starting at the 999,999,999,999,997th bit of Pi: 1110 0110 0010 0001 0110 1011 0000 0110 1001 1100 ^ Quadrillionth bit of Pi 1011 0110 1100 0001 1101 0011or in hexadecimal, starting at the same point: E6216B069CB6C1D3
Steve Finch has written an article about the BBP formula, (upon which Bellard's formula, is based) and the algorithm of Bailey, Borwein, and Plouffe, which we use. A good mathematical reference for this topic is the paper which introduced the world for the first time to this type of calculation, written by Bailey, Borwein, and Plouffe. Available in PDF (193K) and Postscript (182K). Due to the size of the output (many megabytes) produced by PiHex, it is not available for download. (It also makes rather dull reading, consisting of what are, for all practical purposes, random numbers). It is however available upon request, by contacting Colin Percival. |